4.7 Multimedia Resource Function

23.2283GPPIP Multimedia Subsystem (IMS)Release 18Stage 2TS

The architecture concerning the Multimedia Resource Function is presented in Figure 4.7 below.

Figure 4.7: Architecture of MRF

The MRF is split into Multimedia Resource Function Controller (MRFC) and Multimedia Resource Function Processor (MRFP).

Tasks of the MRFC are the following:

– Control the media stream resources in the MRFP.

– Interpret information coming from an AS and S‑CSCF (e.g. session identifier) and control MRFP accordingly.

– Generate of CDRs.

Tasks of the MRFP include the following:

– Control of the bearer on the Mb reference point.

– Provide resources to be controlled by the MRFC.

– Mixing of incoming media streams (e.g. for multiple parties).

– Media stream source (for multimedia announcements).

– Media stream processing (e.g. audio transcoding, media analysis).

– Floor Control (i.e. manage access rights to shared resources in a conferencing environment).

Tasks of an Application Server with regards to MRF are e.g. the following:

– Conference booking and management of booking information (e.g. start time, duration, list of participants)

The protocol used for the Mr and Mr′ reference points is SIP (as defined by IETF RFC 3261 [12], other relevant IETF RFCs, and additional enhancements introduced to support 3GPP´s needs).

The Cr reference point allows interaction between an Application Server and an MRFC for media control. Further information on the Cr reference point is provided in TS 23.218 [71].

The Mp reference point allows an MRFC to control media stream resources provided by an MRFP.

The Mp reference point has the following properties:

– Full compliance with the H.248 standard.

– Open architecture where extensions (packages) definition work on the interface may be carried out.

The protocol for the Mp reference point is described in TS 29.333 [59].